CHAPTER X 

 THE PRELIMINARY SURVEY 



The Drainage Engineer. The services of a professional 

 drainage engineer are well worth their cost. The success of 

 any drainage system depends upon whether it is well planned 

 or not. If not correctly installed, the whole investment may 

 be worthless. Hence a small percentage of this investment 

 paid in fees to those who by training and experience know how 

 the work should be done is money well spent. It is not the 

 purpose of this text to detract from the work of the engineer, 

 but rather to lead to an appreciation of his work. 



There is a difference between surveying and engineering. 

 Surveying includes only the taking and recording of such 

 field observations necessary for the designing of a drainage 

 system. The actual work involved in the designing and 

 execution may truly be called engineering. This latter work 

 involves much skill and experience. 



The Need of a Preliminary Survey. The first step in 

 the drainage of any tract of land is the making of a prelimi- 

 nary survey or an investigation, which should be for the 

 purpose of obtaining a clear idea of the situation and a 

 general knowledge of the nature and amount of drainage 

 which will be required to accomplish the desired purpose. 



The preliminary survey, then, is the basis upon which the 

 next step, involving the actual work of installing the drain- 

 age system, must depend. There are many things to be con- 

 sidered in the preliminary survey, such as information con- 

 cerning the character and value of the land before and after 

 improving. Careful investigations should be made to 



64 



